Electric furnace.



'No. 75 7,621. I PATBNTED 111 11.19, 1904.

' W. s. 11011111 11 12.1. PRIGB.

ELEGTRIG FURNACE. APPLICATION FILED 90,1211, 1902. 30 11013111,. zsnnnTs-snnm 2.

No. 757,621. Patented. April 19, 1904.

,UNITE STATES PATENT OFFICE.

WILLIAM SMITH HORRY AND EDGAR F. PRICE, OF NIAGARA FALLS, NEW 5 YORK, ASSIGNORS TO UNION CARBIDE COMPANY, OF NIAGARA FALLS. NEW YORK, A CORPORATION OF VIRGINIA.

ELECTRIC FURNACE.

SPECIFICATION forming part of Letters Patent No. 757,621, dated April 19, 1904.

Application filed October 11,1902. Serial No. 126,823. (No model.)

TO whom it m concern! carbid, iron, carbid of iron, or other suitable Beit known that we,WILLIAM SMITH HoRRY, material in a molten condition or which may a subject of the King of Great Britain, and be a conducting mixture of lime and carbon .EDGARF. PRICE, acitizen of theUnited States, or merely broken carbon, and this body is residents of Niagara Falls, in the county of maintained by the passage of the current at Niagara and State of New York, have jointly a suflicient temperature to effect the required invented a certain new and useful Electric reaction in adjacent portions of the super- Furnace, of which the following is a specifiposed furnace charge 7. This charge will I cation. I for the production of calcium carbid comprise I Th1s lnvention comprises an electricfurnace any suitable mixture of carbon and lime.

designed for effecting reactions at high tem- Referring now more particularly to Figs.

peratures, and more particularly for forming 1 and 2, the side walls 1 of the furnace are incalcium carbid, the construction of the furdicated as converging to a central contracted nace and the arrangement of its parts being portion, adjacent to which is the electrode 5 I 5 such as to facilitate the tapping of the molten and the tap-hole 9. Other electrodes 4 A of a product of the reaction. polarity opposite to that of the electrode 5 are Calcium carbid attains a fluidity sufficient placed at or near the ends of the furnace. The 6 5 to permit of tapping from the furnace only effect ofthis construction is to reduce the crossat very high temperatures, and constructions sectional area of the conductive body 6 from 2 whereby such necessary high temperature a maximum in the region of the electrodes 4 may be maintained in the vicinity of the tapto a minimum at or near the central electrode hole of the furnace are illustrated in the ac- 5 and to cause the current density and also the 7 companying drawings, wherein energy density to be maintained at a maximum Figure 1 is a horizontal section of one form in the central portion of the conductive body 2 5 of furnace. Fig. 2 is a vertical central sec- 6. Said conductive body is thereby heated at tion of the same. Figs. 3 and 4: are modified this central portion to a relatively high temforms shown in vertical central section. Figs. perature, and the product of reaction, as cal- 5 and 6 illustrate further modifications in vercium carbid, may at this point be most readily tical central section and in horizontal section, withdrawn from the furnace. The same re- 3 respectively. Figs. 7 and 8 show in vertical sult is accomplished if the central electrode 5,

central section and in horizontal section, readjacent to the tap-hole, be omitted, the curspectively, a form of furnace wherein the rent, passing between the electrodes 4. The gradation in current density is effected by the increased current and energy density in the arrangement of the electrodes. contracted portion of the conductor effects. 35 Referring to the figures, the furnace comsuch local increase in temperature as to enable prises a structure having side walls 1 and a the product to be readily tapped from the fur base 2, of refractory material. The base may nace. 5 be provided, as shown in Figs, 3, A, 5, with In Fig. 3a form of furnace is shown wherein fines or openings 3 for the circulation of air the conductive body 6 converges to a central 4 and with a suitable interior facing 8, of recontracted portion, said convergence takingfractory composition. The electrodes 4 5 place in a vertical plane. This form of furmay be inserted in openings in the furnacenace may be rectangular in plan or the side base, as shown in Figs. 1, 2, 3, 5, 6, or may walls also may converge toward the central depend from above, as illustrated in the reelectrode, as in Fig. 1. 45 maining figures, or may extend through the Fig. 4 shows a construction differing in that side walls. As clearly shown in Figs. 3, 4, 5, the central electrode is omitted, the current and 7, the electric circuit is completed through being conducted to and from the furnace by the 9 5 a conductive body 6, which may be calcium electrodes 4 5, situated at or near the ends of.

the furnace. In this case also the highest temperature is developed in a region adjacent to the tap-hole 9. The side walls in this construction may be substantially parallel or they may converge in the manner shown in Fig. 1.

Figs. 5 and 6 show modified constructions wherein the base and side walls incline toward a tap-hole located at or near one end of the furnace, so as to provide for a graduated reduction of the cross-sectional area of the conductor from end to end of the furnace. In this furnace the side walls only may converge toward the tapping end, or the side walls may be substantially parallel, the reduction in cross-sectional area of the conductor being secured by the inclination of the base, or the converging side walls and inclined base may be combined in a single structure.

Figs. 7 and 8 illustrate a form of furnace which may be rectangular in plan and in which the conductive body 6 may be of substantially equal cross-sectional area throughout. In this construction the current passes between a plurality of electrodes 4, connected in parallel to one terminal of the source of current, and a-plurality of electrodes 5, connected in parallel to the other terminal. As a result of this arrangement the maximum current passes between adjacent electrodes near the center of the furnace, the quantity of current passing, and hence the current density and energy density in the conductor, being progressively increased toward the center. It will be clear that in this construction, as in that shown in Figs. 1, 2, 3, and t, the current density and the energy density attain a maximum at or near the central portion of the conductive body, and the furnace product is tapped out, as indicated at 9, at this point or region of maximum temperature. It is obvious that electrodes may be arranged in this manner in a furnace having side walls converging to a central contracted portion or in a furnace of the type illustrated in Fig. 4:, wherein the base alone is inclined or such inclination is combined with convergence of the side walls.

WVhile the operation specifically described is the production of carbid, the furnace is capable of general application, as the formation and withdrawal of any molten furnace product.

lVhile in the operation of the furnaces shown and described the molten product flows out through a tap-hole, and is therefore specified in the claims as withdrawn by gravity, it will be understood that in some cases the movement of the molten material may be assisted by mechanical means. For example, the taphole must be kept clear from obstructions and the flow of the carbid under the action of gravity may be suitably facilitated or assisted.

We are aware that United States Patents Nos. 750,096 and 750, 170, granted January 19, 1904, to Alfred H. Gowles, disclose processes in which an electric current is passed through a charge or pool of electricallyconductive material and in which the density of the electric current increased-within the charge or pool to provide a region of maximum current density. WVe make no claim to anything disclosed in these patents, our claims including features which are specifically novel.

1. An electric-resistance furnace, compris ing a hearth to support a charge or molten product of conductive material, three or more electrodes in contact with said charge or prodnot and so arranged and connected to the source pf electric current as to maintain a re gion of maximum current density in an intermediate portion of said charge or product, and means adjacent to the region of maximum current density for withdrawing the product by gravity, as set forth.

2. An electric-resistance furnace, comprising a hearth to support a charge or molten product of conductive material and of varying cross-section, three or more electrodes in contact with said charge or'prod uctand so arranged and connected to the source of electric current as to maintain a region of maximum current density in an intermediate portion of said charge or product, and means adjacent to the region of maximum current density for withdrawing the product by gravity, as set forth.

3. An electric-resistance furnace, comprising a hearth to support a charge or molten product of conductive material with an intermediate portion of less cross-section than its end portions, a plurality of electrodes in con tact with said charge or product and so arranged and connected to the source of electric current as to maintain a region of maximum current density at said intermediate portion, and means adjacent to said intermediate portion for withdrawing a product by gravity, as set forth.

4:. An electric-resistance furnace, comprising a hearth to support a charge or molten product of conductive material with an intermediate portion of less cross-section than its end portions, three or more electrodes in contact with said charge or product and so arranged and connected to the source of electric current as to maintain a region of maximum current density at said intermediate portion, and means adjacent to said intermediate portion for withdrawing a product by gravity, as set forth.

5. An electric-resistance furnace, comprising a hearth to support a charge or molten product of conductive material, and three or more electrodes arranged to pass superposed electric currents through said charge or product and to maintain therein a region of maximum current density, as set forth.

6. An electric-resistance furnace, comprising a hearth to support a charge or molten product of conductive material, three or more electrodes arranged to pass superposed electric currents through said charge or product and to maintain therein a region of maximum current density, and means adjacent to the region of maximum current density for withdrawing the product by gravity, as set forth.

7. An electric-resistance furnace, comprising a hearth supporting a body of a conductive carbid or carbid-forming material, and three or more electrodes arranged to pass superposed currents through said body and maintain therein a region of maximum current density, as set forth.

8. An electric-resistance furnace, comprising a hearth supporting a body of a conductive carbid or carbid-forming material, three or more electrodes arranged to pass superposed currents through said body and maintain thereinaregion of maximum current density, and means adjacent to the region of maximum current density for withdrawing the product by gravity, as set forth. 4

9. An electric resistance furnace, compris ing a laterally-converging hearth to support a body of conductive material, electrodes arranged to maintain-in said body a region of maximum current density, and means adjacent to said region of maximum current density for withdrawing a product by gravity, as set forth.

10. An electric-resistance furnace,comprising a laterally-converging hearth supporting a pool of a conductive carbid or carbid-forming material, and electrodes arranged to maintain in said pool a region of maximum current density, as set forth.

In testimony whereof we have hereunto signed our names in the presence of two subscribing witnesses.

WILLIAM SMITH HORRY. EDGAR F. PRICE. Witnesses:

GEo. H. DANFORTH, F. B. OCoNNoR. 

